Such a temperature-control unit usually comprises a first contact plate, a second contact plate and at least one plate-shaped thermoelectric transducer which has a first transducer side and a second transducer side, facing away therefrom, wherein the respective thermoelectric transducer is arranged between the first contact plate and the second contact plate in such a way that it is coupled in a heat-transmitting fashion by its first transducer side to the first contact plate, and is coupled in a heat-transmitting fashion by its second transducer side to the second contact plate.
A thermoelectric transducer in this context usually comprises a multiplicity of thermoelectric semiconductor elements with positive and negative doping, which semiconductor elements are connected to one another via conductor brides. These semiconductor elements are expediently enclosed in a hermetically sealed fashion with the conductor bridges in a plate-shaped housing, wherein the large, planar sides of the housing, facing away from one another, form the two transducer sides of the respective thermoelectric transducer. The respective thermoelectric transducer can convert an electric current into a heating current, which is based on the Peltier effect. Correspondingly, such a thermoelectric transducer can also be referred to as a Peltier element. Conversely, such thermoelectric transducers can also convert a heating current into an electric current, which is based on the Seebeck effect. In addition, by using such thermoelectric transducers it is therefore possible, by means of corresponding energization, to conduct away heat, that is to say to cool, selectively on the one transducer side and to feed in heat, that is to say to heat, on the other transducer side. Such thermoelectric temperature-control units, which are expediently equipped with a plurality of such thermoelectric transducers, can therefore be used in temperature-control devices, for example, to cool a heat source or to heat a heat sink. Likewise, by using such a temperature-control device, it is conceivable to utilize the temperature difference between a heat sink and a heat source to generate electrical energy.
In the case of high-power batteries such as are applied, for example, in electric vehicles, a large amount of heat is produced which has to be conducted away in order to improve the functionality, power and service life of the battery. In addition, at low ambient temperatures there is also definitely a need to raise the temperature of such a high-power battery to an operating temperature, that is to say to heat it, so that it can produce its power. Accordingly, such temperature-control devices can preferably be used in high-power batteries of this type in order to heat and cool them, as appropriate. Since such a temperature-control device can cool and heat according to requirements, the term “temperature-control” includes the terms “cool” and “heat” in the present context.
It is problematic with such temperature-control units that the contact plates, on the one hand, and the thermoelectric transducers, on the other, are subjected to different temperatures and accordingly different, thermally conditioned expansion effects. In particular, relative movements can occur here between the respective thermoelectric transducer and the contact plates. Such relative movements can adversely affect the heat-transmitting coupling between the transducer and the contact plates.
A temperature-control unit of the generic type is known, for example, from DE 10 2013 212 511 A1. In order to reduce the influence of thermal expansion effects, there is provision in the known temperature-control device to segment the respective contact plate using expansion joints, and to couple the individual segments to one another using spring structures. The implementation of such a design is comparatively costly.